Six-Lens Image Pickup Lens with Aspherical Inflection Points
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Solution Overview
Problem
Existing compact image pickup lenses face challenges in achieving both reduced size and high optical performance, particularly in correcting various aberrations such as Petzval image plane inclination, coma aberration, and chromatic aberration, due to limitations in lens configuration and material usage.
Innovation Solution
A six-lens configuration is adopted, with specific refractive powers and aspherical shapes, including a first lens with positive power, followed by lenses with positive or negative refractive power, and a sixth lens with negative power and an aspherical shape, optimized to allocate power between lenses and correct aberrations, using resin or glass materials to enhance optical performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a five-lens configuration with two negative power lenses is used, then the lens structure is simpler, but Petzval image plane inclination is not sufficiently corrected
Solution Approach 1:
The lens system is divided into six distinct lens elements with specific positive and negative power groups. The sixth lens element is further segmented with an aspherical surface containing inflection points, allowing independent optimization of different zones of the lens to correct image plane inclination while maintaining overall system manageability.
Solution Approach 2:
The sixth lens element incorporates an aspherical surface with inflection points instead of a simple spherical or conical shape. This curved surface geometry enables precise control of light ray paths to correct Petzval inclination, achieving a flat image plane without requiring excessive lens complexity.
2Manufacturing precision
If positive refractive power is concentrated on the first lens to correct Petzval image plane, then image plane flatness improves, but coma aberration increases
Solution Approach 1:
The refractive power is segmented across multiple lens elements rather than concentrated in one lens. The system includes both positive and negative power lenses distributed throughout the six-element configuration, with the sixth element providing additional correction capability through its aspherical surface with inflection points.
Solution Approach 2:
Different zones of the optical system are assigned different functional qualities. The first lens provides initial power and some aberration control, while the sixth lens with its specialized aspherical surface containing inflection points provides localized correction for image plane flatness, allowing each element to optimize its specific function without compromising overall performance.
3Reliability
If more lenses with negative refractive power are added to correct aberration, then optical performance improves, but lens size increases
Solution Approach 1:
The sixth lens element employs an aspherical surface with inflection points that provides enhanced aberration correction capability within a compact form. This sophisticated surface geometry allows a single lens element to perform the optical correction function that would traditionally require multiple additional lenses, thereby maintaining short total optical length while achieving superior aberration control.
Solution Approach 2:
The sixth lens element with its aspherical surface containing inflection points serves multiple functions simultaneously: it provides negative refractive power for overall focal length control, corrects image plane inclination through its specialized surface geometry, and contributes to coma and spherical aberration correction. This multi-functionality reduces the need for additional dedicated correction lenses.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution enables a compact image pickup lens with favorable correction of various aberrations, suitable for high-pixel-density image pickup devices, achieving high optical performance and cost-effectiveness.
Implementation Method 1
a sixth lens having negative refractive power and having optical surfaces, an image-sided surface of the optical surfaces having an aspherical shape with one or more inflection points other than an intersection point of the image-sided surface and an optical axis
Data Source
AI summary
An image pickup lens includes: in recited order from object plane toward image plane, a first lens having positive refractive power; a second lens having positive or negative refractive power; a third lens having negative refractive power; a fourth lens having negative refractive power; a fifth lens having positive refractive power; and a sixth lens having negative refractive power and having optical surfaces, an image-sided surface of the optical surfaces having an aspherical shape with one or more inflection points other than an intersection point of the image-sided surface and an optical axis.